Spindle motor, and disk drive apparatus including the spindle motor

Abstract

A spindle motor includes a shaft arranged to extend in an axial direction, and a base portion arranged to define a portion of a housing, and including a through hole in which the shaft is inserted. A fixing region is defined between an inner circumferential portion of the base portion and a lower portion of the shaft. The fixing region includes a press-fitting region and an adhesion region defined on a lower side of the press-fitting region and in which a seal gap is defined between the inner circumferential portion of the base portion and the lower portion of the shaft. The seal gap is arranged to gradually decrease in radial width with increasing height. The seal gap is arranged to include an adhesive arranged therein over an entire circumference thereof.

What is claimed is: 
     
       1. A spindle motor for use in a disk drive apparatus to drive a disk, the disk drive apparatus including a housing defining an interior space, the spindle motor comprising:
 a stationary portion including a shaft arranged to extend in an axial direction; 
 a base portion arranged to define a portion of the housing, and including a through hole in which the shaft is inserted; and 
 a rotating portion arranged to rotate about a central axis with respect to the stationary portion through a bearing mechanism; wherein 
 the shaft includes:
 a non-through hole portion arranged to extend downward from an upper end of the shaft; 
 a first connection channel arranged to extend from the hole portion in a radial direction to connect the hole portion with an interior of the bearing mechanism; and 
 a second connection channel arranged to extend from the hole portion in the radial direction to connect the hole portion with a space defined on a lower side of the bearing mechanism; and 
 
 gas is permitted to pass into the interior space of the housing through the hole portion and the second connection channel after being fed into the through hole portion from an outside of the housing. 
 
     
     
       2. The spindle motor according to  claim 1 , wherein
 the base portion includes an inner circumferential portion arranged to define the through hole, the inner circumferential portion and a lower portion of the shaft defining a press-fitting region therebetween; and 
 an axial extension range of the hole portion is arranged so as not to overlap with the press-fitting region. 
 
     
     
       3. The spindle motor according to  claim 2 , wherein an axial length of the hole portion is greater than an axial length of a solid region which does not include a through hole defined on a lower side of the hole portion. 
     
     
       4. The spindle motor according to  claim 1 , wherein
 the base portion includes an inner circumferential portion arranged to define the through hole, the inner circumferential portion and a lower portion of the shaft defining a press-fitting region therebetween; and 
 an axial length of a range over which an axial extension range of the hole portion and the press-fitting region overlap with each other is about half or less than half an axial length of the press-fitting region. 
 
     
     
       5. The spindle motor according to  claim 4 , wherein an axial length of the hole portion is greater than an axial length of a solid region which does not include a through hole defined on a lower side of the hole portion. 
     
     
       6. A disk drive apparatus comprising:
 the spindle motor of  claim 1  arranged to rotate a disk; 
 an access portion arranged to perform at least one of reading and writing of information from or to the disk; 
 a clamper arranged to clamp the disk to the spindle motor; and 
 a housing arranged to contain the disk, the spindle motor, the access portion, and the clamper. 
 
     
     
       7. The disk drive apparatus according to  claim 6 , wherein
 the housing includes a housing member arranged to cover an upper side of the spindle motor; 
 an upper portion of the hole portion includes a screw hole portion; and 
 the housing member and the shaft are fixed to each other through a screw inserted into the screw hole portion. 
 
     
     
       8. The disk drive apparatus according to  claim 7 , further comprising a sealant arranged at all circumferential positions between the screw hole portion and the screw, or at all circumferential positions between the housing member and a head portion of the screw.